1. Field of the Invention
The present invention relates to a load control device for control of the amount of power delivered from an alternating-current (AC) power source to an electrical load, and more particularly, to a load control device having a radio-frequency (RF) communication circuit to receive RF messages wherein the communication circuit includes an antenna which is electrically isolated from the AC power source.
2. Description of the Related Art
Typical load control devices are operable to control the amount of power delivered to an electrical load, such as a lighting load or a motor load, from an alternating-current (AC) power source. Many of these load control devices comprise communication circuits for receiving or transmitting digital messages via a communication link. Such communication links may be wired or wireless (e.g., radio frequency, infrared, etc). In order to receive or transmit digital messages via a wireless radio-frequency (RF) communication link, a load control device requires an antenna. Some antennas may reside fully within an enclosure of the load control device, whereas other antennas may extend fully or partially outside the enclosure. Because load control devices are coupled to the AC power source, an antenna extending outside the enclosure of a load control device should be electrically isolated from the AC power source for safety reasons. The use of isolation transformers or optocouplers are well known techniques that can be used to electrically isolate the AC power source from other elements of a load control device, however such prior art isolation techniques can be costly. Therefore, there exists a need for a load control device having an antenna which is electrically isolated—in a low cost manner—from the AC power source.